High-tension conductor



Feb. 24, 1931. J. ZAGORSKI HIGH TENSION CONDUCTOR Filed Feb. 1. 1929 gwvantor,

7 Patented Feb. 24, 1931 UNITED STATES lfATENT. OFFICE Joann: zasoasn, or rumour-cranium, esmlm man-rmrox corrmrc'ron This invention relates to a high-tension conductor.

For conducting hi -tension electric energ it is usual to emp oy conductors of large diameter, which may also be designed as ho low conductors. In order to prevent, as far as possible, 1 of ener through radiation, the smoothest possib e surface is given to both solid and hollow conductors by mak- 10 ing the outer layer at least of the conductor, of special strip sections. wing to the large diameters employed and the low flexibility of the strip sectlons, such conductors are naturally far more rigid than the conductors generallj employed for lower voltages and constructedof laid round p 11; has hitherto been considere that h tension conductors alsoought to be made as flexible as possible; and in where the 3 outside layer or sheath of the conductor was madein the usual way, byv laying, attempts were made to attain this result by employmg "thelarg est possible 'number'of strips for the V covering layer. Thus for example, solid conductors with an external diameter of about a 32 mm. (steel-aluminium conductors) had a covering layer of up to 48 wires, and hollow i conductors of'the type used in Germany, with jan e'xternal diameter of 42 mm. had an outer layer of atleast 24 wires. I Ithas transpired that these conductors are still subject to certaindrawbacks liable to endanger their life considerably. In particular, torsional stresses are set up in these by the rope tension, in consequence of the twist produced in laying. These forces setup a considerable stressing ofthe conductor just 'in front, of the places where it is gripped in the suspension and straining clamps. through permanent flexions and the like, which stressing could only be partially counteracted by correspondingly strengthening the design of the. clamping members.

- A. similarly injurious e'fi'ect is produced bythe oscillations (set up by thewind and the like) always observable in the sections between the straining devices, and especially in overhead conductors of large cross section. In such cases the material which sufiers most is that of the insulating chains, through the sudden the oscillation between the Application fled Iebrury 1, ll, lerlal Io. sag-hand in Germany Iay 8, 1927.

tensional stresses which inevitably result from said oscillation.

It has now been ascertained that when conductors are employed, which are made of str p sections, or-with a covering layer of stng sections, the torsional stresses oecurring m t e overhead conductors when in position for use can be prevented, in-a practically complete manner, and the injurious effects of the oscillations of the con uctor prevented to some extent, by extremely simple measures; all thatis necessary being merely to employ sufliciently wide strips in making the outside layer.

According to the present invention, the widthof theflat wires ofwhich the outer- ,most layer, at least, of the conductor is compesed,'should-be such that the ratio of the diameter D of the conductor, in millimetres,- to the number Z of the wires in the outer layer should exceed 2, that is to say.-

It has been iound of particular advantage forthe ratio D to Z to be about 4 The hi tension conductors to which-the resent 1nvention has reference are tobe un erstood as those having a greater diameter than about mm. 7 I

It has "unexpectedly transpired that the greater rigidity of conductors constructed in accordance with the invention offers no substantial hindrance to their transport and erection. As before, the conductors can be coiled on suitable drums and the dreaded gapin between the individual sections of the outer ayer can also be prevented, especially when their divergence in the radial direction is prevented by a suitable desi for the strip sections of the outer layer, or example by providing them with tongue and groove )OilltS.

7 ,Moreover, the greater rigidity of the conductors constructed in accordance with the invention has a powerful damping effect on intsof support. The small number of jomts-between the strips also naturally makes the surface of the conductors substantially smoother, so

that the electrical losses by radiation are vided with tongues and grooves at their conlow. A further advantage is that the cost t'acting edges,-e qual in number to one-fourth of manufacture vof the conductors is cheaper, to one-half of the number whichdndicates owing to the greatly reduced number of the the diameter of the conductor in m1l l1meters.' 5 wire sections of which the conductors are In testimony whereof I aflix mg silgnature. 70

composed. JOHANN ZA 9 SKI.

In order-more -clearly to understand the v invention. reference is made tothe accompanying drawings in which I m Fig. 1 shows the cross section of a solid conductor with an external diameter of 25 mm., the covering layer, a, of which is built up in accordance with the invention, 'of six strip sections.

' Fig. 2 represents a hollow conductor,- 32 9 mm. in diameten'and with eight strip sections (1 built up in the same manner. 7

Figs. 3 and 4 represent the moment of re-. sistance .of similar cross sections of st'rips in 85 I0 relation to their axis. From these figures it can be seen that the moment of resistance, referred tothe axis w v in Fig. 3 is a multiple of that represented in Fig. 4, which is referred to the axis 31-111.

In stretched laid conductors.'the rope ten- 90 sion acts by tending to straighten out again the wires of the conductor which the opera tion of laving has disposed in approximately a spiral line of steep pitch. Consequentlv. since the wires in the conductor are. subjected to flexion 'by the rotational forces set up by the rope t'ension, such flexion norresponding to the moment of resistance of their cross section. referred to the 35 axis M, the invention'enables the moment of resistance of the wires to be increased, by increasing the dimension a to such an extent that the torsional stresses are counteracted to a considerable degree or with practical 4 completeness.

The high-tension conductors under consideration are particularly those employed for working voltages of 150 kw. or higher, and having an external diameter of at least 20 mm. Under these working conditions,

the-hollow conductor of the inveiition'has proved particularly advantageous.

' I claim I 1-. A hollow high tension conductor having a diameter of more than 20 comprising 'a plurality of spirally arranged interlocking strips eqiial in number to one-fourth to onehalf of the number which indicates the diameter of the conductor in millimeters.

2. "A hollow high tension conductor having a diameter more than 20 mm. comprising a plurality of spirally arranged strips provided with tongues and grooves at theircon tacting'edges, equal in number to one-fourth to one-half of the number which indicates the diameter of the conductor in millimeters.

3. A- flexible self-sustaining hollow conductor havin a diameter of more than 20 mm. comprising a plurality of interlocked a spiral longitudinally extending strips pro-- M, 

